Staggering tasks confronted the people of the United States, North and South, when the Civil War ended. About a million and a half soldiers from both sides had to be demobilized, readjusted to civilian life, and reabsorbed by the devastated economy. Civil government also had to be put back on a peacetime basis and interference from the military had to be stopped. The desperate situation of the South had eclipsed the fact that reconstruction had to be undertaken also in the North, though less spectacularly. Industries had to adjust to peacetime conditions; factories had to be retooled for civilian needs. Financial problems loomed large in both the North and the South. The national debt had shot up from a modest $ 65 million in 1861, the year the war started, to nearly $ 3 billion in 1865, the year the war ended. This was a colossal sum for those days but one that a cautious government could pay. At the same time, war taxes had to be reduced to less burdensome levels. Physical devastation caused by invading armies, chiefly in the South and border states, had to be repaired. This difficult task was ultimately completed, but with discouraging slowness. Other important questions needed answering. What would be the future of the four million black people who were freed from slavery? On what basis were the Southern states to be brought back into the Union? What of the Southern leaders, all of whom were liable to charges of treason? One of these leaders, Jefferson Davis, president of the Southern Confederacy, was the subject of an insulting popular Northern song, 'Hang Jeff Davis from a Sour Apple Tree,' and even children sang it. Davis was temporarily chained in his prison cell during the early days of his two-year imprisonment. But he and the other Southern leaders were finally released, partly because it was unlikely that a jury from Virginia, a Southern Confederate state, would convict them. All the leaders were finally pardoned by President Johnson in 1868 in an effort to help reconstruction efforts proceed with as little bitterness as possible. What does the passage mainly discuss?